For cleaning compositions such as hand dishwashing liquids, a correct consistency or viscosity is very important to consumers' perception of the products. The desired viscosity, expected by the consumer, should not be too thick or too thin. The consumer desires a liquid viscosity providing liquid pourability and ease of dissolution in water. To be consumer acceptable, liquid cleaning products like hand dishwashing liquids must be able to provide good cleaning and manifest the foaming and rinsing properties which consumers today expect from a commercial liquid detergent. Finally, the dissolution rate of the liquid in water is desired to be rapid so that foam generation is not delayed. Foam is a signal to consumers that the detergent is high quality. Pourability and dissolution are in part linked to liquid viscosity.
In addition, there is a general desire for cleaning formulations that are environmentally sustainable and so have reduced impact to the environment but exhibit satisfactory performance and aesthetics, at least comparable to previous less sustainable compositions.
Some liquid consumer products are sold in a concentrated form and the consumer dilutes the concentration at home. This enables products to be sold in a smaller package to reduced packaging waste, with corresponding reduced transportation costs.
A problem is created, however, in preserving the composition from bacterial growth once the composition is diluted. While preservatives can be added to the composition to preserve the initial composition, upon dilution the level of preservative can be too low to preserve the diluted composition. Adding additional preservatives is not an option across all dilution factors because the amount of preservative that can be included in the original composition has a maximum amount that is controlled by regulations. Even starting at the maximum amount of preservative, the concentration of preservative in the diluted form may be too low.
There is a need for cleaning compositions, in particular hand dishwashing liquids, which can be sold in concentrated form and are readily dilutable at home by the consumer to achieve the desired viscosity properties, which properties not only present in the initial concentrated composition but also are achieved over a wide dilution range along with the composition being preserved at the diluted concentration.